A hybrid vehicle may provide regenerative driveline braking to slow a vehicle. During regenerative braking, a vehicle's kinetic energy may be converted to electrical energy. The electrical energy is stored in an energy storage device where it may be held until it is needed to supply power to the vehicle or perform some other function. The energy storage device may have capacity constraints so that it may store a limited amount of electrical energy. Consequently, it may be desirable to continue to convert the vehicle's kinetic energy into electrical energy even though the energy storage device is approaching conditions where additional charging may not be desired. However, the energy storage device may degrade if it is over charged.
The inventors herein have recognized the above-mentioned disadvantages and have developed a method for controlling driveline braking, comprising: providing driveline braking via an electric machine while rotation of an engine is stopped; and automatically activating a device to consume charge provided via the electric machine while the electric machine is providing driveline braking.
By automatically activating a device to consume charge from an electric machine while the electric machine is providing driveline braking, it may be possible to extend regenerative braking. For example, it may be possible to activate windscreen heaters to consume excess electrical energy produced via an electrical machine providing driveline braking so that regenerative braking may be extended.
The present description may provide several advantages. Specifically, the approach may reduce the need to transition between driveline braking modes. Further, the approach may extend the life of friction braking devices. Further still, the approach may reduce driveline wear, thereby increasing the operating life of the driveline.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.